The trans mount is comparatively a piece of cake and can (and should) be done independently of the engine mounts. It's basically the third leg of a 3-legged mounting system (L and R engine mounts, trans mount on the tail of the tranny).
To replace it, you simply support the tranny (jack it up a little), remove the trans-mount nut at the top of the mount, remove the four crossmember-chassis bolts, remove crossmember, take out two bolts that attach the mount to the crossmember, remove old mount.
"Installation is reverse of disassembly," to quote Mr. Haynes.
I leave the mount loose until everything is in place, then tighten it all down.
Hope this helps.
-Dan
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1976 w115 300D 4-speed conversion!!
1985 w123 300TD 4-speed conversion!!
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